Comparison of the Alfven Wave Solar atmosphere Model (AWSoM) with Parker Solar Probe Observations

Abstract:

We compare Alfvén Wave Solar atmosphere Model (AWSoM) simulations with the fourth orbit of NASA’s Parker Solar Probe (PSP). The first three PSP encounters had perihelia of more than 35 Rsun. The fourth perihelion was closer to the Sun at 26.8 Rsun. AWSoM allows us to check whether or not the coronal heating can be explained via Alfvén wave turbulence. In the AWSoM model, the coronal heating and acceleration is addressed via low-frequency, reflection-driven Alfvén waves. The nonlinear interaction of counter-propagating waves results in a turbulent energy cascade. The dissipated wave energy is then apportioned to electron and anisotropic proton temperatures. We check the ability of the simulations to reproduce the observed plasma mass density, velocity, and magnetic fields, temperature anisotropy, and wave turbulence levels. To deduce the sources of the solar wind observed by PSP we use the AWSoM model to determine the field line connectivity between PSP locations and the Sun. We will also describe the large-scale structures that PSP might have passed through, for instance whether PSP was in the fast or slow wind and when PSP crossed the heliospheric current sheet.

This work was supported by NASA grant NNX17AI18G.